v1.0.0-rc.168 (#78)

* rugnux is substantially faster - a corpus of 145 rotation datasets processes in about two thirds of the time - with identical results.
* A crystal whose lattice looks more symmetric than it is because the beam centre is off is no longer processed on the wrong cell.
* rugnux prints at startup, and writes at the foot of every results report, a short acknowledgement of the X-ray research community whose methods it implements and of the open-source projects it builds on; `ACKNOWLEDGEMENT.md` now ships in every package beside `LICENSE` and `THIRD_PARTY_NOTICES.md`.

Reviewed-on: #78
Co-authored-by: Filip Leonarski <filip.leonarski@psi.ch>

tests/BeamCenterFromBackgroundTest.cpp

@@ -164,3 +164,21 @@ TEST_CASE("BeamCenterFromBackground_RecoversACentreFarFromTheDetectorMiddle", "[
     CHECK(estimate->beam_x_pxl == Catch::Approx(geom_true.GetBeamX_pxl()).margin(2.0));
     CHECK(estimate->beam_y_pxl == Catch::Approx(geom_true.GetBeamY_pxl()).margin(2.0));
 }
+
+// The fit is accumulated over row blocks so that a machine with more cores gives the same answer as
+// one with fewer: the blocks are a property of the image and the fold runs over them in order.
+TEST_CASE("BeamCenterFromBackground_DoesNotDependOnTheThreadCount", "[BeamCenter]") {
+    DiffractionExperiment x = TestExperiment();
+    PixelMask pixel_mask(x);
+
+    const DiffractionGeometry geom_true = OffsetBy(x.GetDiffractionGeometry(), 3.0f, -2.5f);
+    const auto projection = SynthesiseProjection(x, pixel_mask, geom_true, 60.0f, 1.0f);
+    const auto one = FindBeamCenterFromBackground(x, pixel_mask, projection, 1);
+    const auto many = FindBeamCenterFromBackground(x, pixel_mask, projection, 8);
+
+    REQUIRE(one.has_value());
+    REQUIRE(many.has_value());
+    CHECK(one->beam_x_pxl == many->beam_x_pxl);
+    CHECK(one->beam_y_pxl == many->beam_y_pxl);
+    CHECK(one->sigma_pxl == many->sigma_pxl);
+}